1. Field of the Invention
This invention relates to a halogen-free crosslinked resin composition, which has flame retardancy, as well as an electrically insulated wire (insulated wire) and a cable covered with that halogen-free crosslinked resin composition (in particular, an insulated wire for vehicle and a cable for vehicle).
2. Description of the Related Art
Awareness of environmental issues has been increasing worldwide, and there has been a demand for use of a so-called halogen-free material, which is free from halogen gas emissions when burnt, for an insulated wire and a cable. For example, an insulated wire using a halogen-free flame retardant such as a metal hydroxide or the like is known as disclosed by JP-A-2010-97881.
In order to achieve high flame retardancy enough to suppress the propagation of flames during a fire, it is necessary to fully fill such a halogen-free flame retardant, but there has been such a problem that fully filling thereof lowers mechanical properties and also lowers melt flow properties, thereby constrains a molding machine.
Meanwhile, the insulated wires and cables to be used in railroad vehicles, automobile vehicles or the like are required to have high oil resistance and low temperature properties, depending on an environment for the use.
It has been known that a polymer having high crystallinity or a polymer having high polarity may be used in order to achieve the high oil resistance. Also, it has been known that a material having low glass transition temperature (Tg) may be used in order to achieve low temperature properties.